The present invention relates to implements for degating or removing the risers from castings and more specifically relates to hammers used for such removal.
It is common practice to manufacture iron castings, such as ductile iron castings, with large iron risers attached to critical areas of the castings to eliminate casting shrinkage during cooling. Risers are typically broken off manually by means of a sledge hammer. These large risers often require numerous blows to be applied to them in order to separate them from the casting and thus making the "cleaning" up of the castings a labor-intensive procedure resulting in increased manufacturing cost. Another problem with using sledge hammers for removing gates and risers from castings is that the castings must cool down for an extended length of time after being removed from the mold so that the metal will break instead of tear when hit with a sledge hammer.
Furthermore, wielding large hammers to break off chunks of iron is not a particularly safe activity requiring the work space to be cleared of and shielded from other personnel; and even with adequate training and instruction a worker is apt to undergo injury due to misdirected blows which result in inordinate stresses on the body or due to getting struck by metal pieces that take unusual trajectories when they break from the casting.
While powered devices such as hydraulic wedges, hydraulic reams, rotating table mill heads, hydraulic concrete breakers and metal shears are being used by foundries to remove gates or risers from castings, each has limitations to general use in the degating process.